Generally, since signaling transceiving is performed via a direct link between a fixed base station and a mobile station in a wireless communication system, it is facilitated to configure a highly-reliable wireless communication link between a base station and a mobile station. Yet, since a location of a base station may be fixed in a wireless communication system, a wireless network configuration is less flexible. Moreover, in a wireless environment having a considerable fluctuation of traffic distribution or call demand level, it is difficult to provide an efficient communication service. In order to overcome these disadvantages, it is able to apply a multi-hop type data transfer scheme to a general cellular wireless communication system using a fixed relay station, a mobile relay station or general mobile stations.
A wireless communication system, which adopts a multi-hope relay scheme, is able to reconfigure a network to promptly cope with a communication environment change and is also able to operate and manage an overall wireless network more efficiently.
For instance, a wireless communication system, which adopts a multi-hop relay station scheme, extends a cell service area and increases a system capacity. In particular, if a channel status between a base station and a mobile station is poor, it is able to provide the mobile station with a wireless channel having a better channel status by configuring a multi-hop relay station path via a relay station by establishing the relay station between the base station and the mobile station. Moreover, by applying a multi-hop relay station scheme to a cell boundary area having a poor channel status from a base station, it is able to provide a faster data channel and it is also able to extend a cell service area.
A relay station is the technology introduced for eliminating a shade area in a mobile communication system and is widely used. Compared to an old system which is limited to a repeater function of sending a signal by simply amplifying the signal, a current system has evolved into a more intelligent system.
Moreover, a relay station technology is mandatory for a next generation communication system to reduce a cost for an extension of base station installations and a maintenance cost of a back hole communication network and is also mandatory for a service coverage enlargement and a data processing rate enhancement. As the relay station technology is further developed, it is necessary for a new wireless communication system to support a relay station used for a conventional wireless communication system.
A legacy system is the system that follows a conventional specification and corresponds to a conventional system. For instance, IEEE 802.16e system corresponds to a legacy system as well. Yet, the legacy system is not limited to the IEEE 802.16e system only. It is able to install a new system evolved further from a previous system in a region where a legacy system is installed. In this case, the new system should be able to support a service for both of a legacy terminal and a new mobile station.